Use of refrigeration loops to chill inlet air to gas turbine

ABSTRACT

As described herein, a method and system for operating a refrigeration system are provided. In the present methods and systems, a portion of the refrigerant from the refrigeration system is used for reducing the temperature of inlet air entering the gas turbine. The refrigeration system disclosed herein can be used for LNG production, air separation, food storage, or ice-making.

This application is co-pending to U.S. patent application entitled “Method to Maximize LNG Plant Capacity in All Seasons”, filed 30 Dec. 2010, Attorney Docket No. 70205.0221US01, the contents of which are herein incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present application relates to a method and system which maximizes gas turbine output for a refrigerant loop. The method consumes a small amount of refrigerant and utilizes the refrigeration to chill the inlet air to the gas turbine (GT) machines used in the refrigeration system. This approach enhances the gas turbine power output and efficiency which, in turn, increases the production of the plant. The gain in efficiency in production can compensate for the consumption of refrigerant.

BACKGROUND OF THE INVENTION

Gas turbines are commonly used for driving compressors in refrigeration systems. For example, gas turbines are used in to drive refrigeration compressors in LNG production, air separation, food storage and ice making.

Gas turbines are constant volume machines and their output depends on the mass flow of air through the turbine. Over the years various technologies have been developed to increase the amount of useful power that gas turbines are able to produce. One way of increasing the power output of a gas turbine is to cool the turbine inlet air prior to compressing it in the compressor. Cooling inlet air increases the air mass flow through the turbine, increasing turbine output and reducing heat rate. Cooling the inlet air also increases the turbine's efficiency.

Degradation of gas turbine output power with a rise in ambient air temperature further poses a serious problem. Cooling inlet air can address the problems associated with rising ambient temperatures.

Various systems have been devised for chilling the inlet air. One system uses evaporative cooling, another uses a chiller to chill water that is then run through a coil. However, a continuing need exists for a turbine inlet air cooling system and method which is efficient and does not drain the system of power.

SUMMARY OF THE INVENTION

As described herein, a method and system for maximizing gas turbine output for a refrigeration loop are provided. The method and system provide a gain in energy efficiency of the gas turbine while compensating for an amount of energy required for consuming a portion of refrigerant.

In one embodiment disclosed herein is an integrated system for refrigeration. The system comprises (a) a refrigeration system comprising a refrigeration loop for air-chilling; (b) a gas turbine for driving a compressor for the refrigeration system; (c) a heat exchanger for consuming a portion of refrigerant from the refrigeration system and cooling a heat transfer fluid; and (d) a second heat exchanger for reducing the temperature of inlet air entering the gas turbine with the heat transfer fluid.

In another embodiment disclosed herein is an integrated method of maximizing gas turbine output for a refrigeration loop. The method comprises (a) operating a refrigeration loop for chilling processes; (b) operating a gas turbine to drive a compressor for a the refrigeration loop; (c) gasifying a portion of refrigerant from the refrigeration system; and (d) reducing the temperature of inlet air entering the gas turbines by exchanging heat with the gasified portion of refrigerant either directly or indirectly.

In an additional embodiment disclosed herein is an integrated method of operating a gas turbine used in a refrigeration loop. The method comprises (a) operating a gas turbine to drive a compressor for a refrigeration system comprising a refrigeration loop and (b) chilling inlet air entering the gas turbine by (i) exchanging heat with a refrigerant in the refrigeration loop; or (ii) cooling a heat transfer fluid with a refrigerant in the refrigeration loop, and chilling inlet air entering the gas turbine by exchanging heat with the heat transfer fluid; or both (i) and (ii). In the method the refrigerant in the refrigeration loop comprises methane, ethane, propane, ammonia, a hydrofluorocarbon, a chlorofluorocarbon, a hydrochlorofluorocarbon, a bromofluorocarbon, a bromochlorofluorocarbon, or any combination thereof; and the heat transfer fluid comprises methanol, ethanol, a glycol and water mixture, or any combination thereof. In this method the gas turbine and refrigeration system can be used to produce LNG and the method further comprises cooling and condensing a natural gas stream by reducing the temperature of the natural gas using the refrigeration system.

In another embodiment disclosed herein is an integrated liquefied natural gas (LNG) system. The system comprises (a) an inlet stream comprising natural gas; (b) a refrigeration system for reducing the temperature of the natural gas and condensing the natural gas to produce LNG; (c) a gas turbine for driving a compressor for the refrigeration system; (d) a first vaporization heat exchanger for regasifying a portion of the LNG and cooling a heat transfer fluid; (e) a second vaporization heat exchanger for consuming a portion of refrigerant from the refrigeration system and cooling the heat transfer fluid; and (f) a third heat exchanger for reducing the temperature of inlet air entering the gas turbine with the heat transfer fluid. The integrated system can further comprise an outlet pipeline for supplying the regasified portion of the LNG to the domestic gas market.

In a further embodiment discloses herein is an integrated method for operating a liquefied natural gas (LNG) plant, the method comprising: (i) cooling and condensing a natural gas stream in a refrigeration system to produce liquefied natural gas (LNG); (ii) operating a gas turbine to drive a compressor for the refrigeration system; (iii) regasifying a portion of the LNG; (iv) consuming a portion of the refrigerant from the refrigeration system; and (iv) reducing the temperature of inlet air entering the gas turbine by exchanging heat with the regasified portion of the LNG and with the consumed portion of the refrigerant directly or indirectly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an embodiment of the proposed refrigeration loop.

FIG. 2 is a graph showing the monthly temperature variations at three locations for LNG and domestic natural gas production.

DETAILED DESCRIPTION OF THE INVENTION

In the present methods and systems, a portion of refrigerant from the refrigeration system is utilized to cool the inlet air to the gas turbines in the refrigeration system, either directly or indirectly.

DEFINITIONS

In accordance with this detailed description, the following abbreviations and definitions apply. It must be noted that as used herein, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “gas turbine” includes a plurality of such.

Unless otherwise stated, the following terms used in the specification and claims have the meanings given below:

“LNG” is liquefied natural gas. Natural gas from the well can consist of various hydrocarbons and contaminants; natural gas for the domestic market is comprised primarily of methane. At ambient temperature and pressure, LNG exists as a gas, but it can be cooled and/or pressurized to provide a liquid, which facilitates storage and transportation.

“Remote location or market” means a location that is not readily accessible or economically feasible to access by pipeline. For example, a remote location or market can be at least over a thousand miles away from the natural gas source and/or is separated in geography such that it is not accessible by pipeline, for example, separated by oceans or other large, deep bodies of water.

“Local market” means a location that is within a distance and geography from the natural gas source so that the natural gas may be supplied as a gas by pipeline. For example, local markets can be at any distance within several thousand miles from the natural gas source and is accessible by pipeline.

“Direct” in the context of heat exchange means that the heat exchange between the refrigerant and the inlet air is direct with no intermediate heat transfer fluid involved.

“Indirect” in the context of heat exchange means that the heat exchange between the refrigerant and the inlet air involves an intermediate heat transfer fluid. Accordingly, the temperature of inlet air entering the gas turbine is reduced by exchanging heat with the refrigerant through a heat transfer fluid system.

“Integrated” means that the steps or units of the system or interconnected so that when operating together greater efficiencies are realized in comparison to when operating independently.

A “hydrofluorocarbon” means a compound containing carbon, hydrogen, and fluorine.

A “chlorofluorocarbon” means a compound containing carbon, hydrogen, fluorine, and chlorine.

A “bromofluorocarbon” means a compound containing carbon, hydrogen, fluorine, and bromine.

A bromochlorofluorcarbon means a compound containing carbon, hydrogen, fluorine, bromine, and chlorine.

“Substantially all” means at least 90% and up to 100%.

“Optional” or “optionally” means that the subsequently described event or circumstance may, but need not, occur, and that the description includes instances where the event or circumstance occurs and instances in which it does not.

Most refrigeration systems utilize one or more gas turbines to drive the refrigeration compressors. Power generators are also driven by gas turbines in refrigeration systems. The combined output and efficiency of all gas turbines determines the total capacity of the refrigeration system. Refrigeration systems driven by one or more gas turbines are utilized in LNG production, air separation, food storage, and ice-making.

For example, LNG plants utilize one or more gas turbines to drive the refrigeration compressors required to liquefy the natural gas and power generators are also driven by gas turbines in the LNG plants. In LNG plants, a portion of the natural gas collected may also be utilized as a fuel for power generation for the LNG plant, including for the gas turbines. The combined output and efficiency of all gas turbines determines the total capacity of the LNG plant.

The present application provides a method and a system which maximizes refrigeration systems driven by gas turbines in all seasons. In the present methods and systems substantially a small portion of refrigerant from the refrigeration system is consumed and the cooling from this process is used to reduce the temperature of inlet air entering gas turbines of the refrigeration system. The portion of refrigerant utilized for cooling the inlet air may be recycled to the refrigeration system.

Accordingly, with the present method and system, integration is utilized to increase the gas turbine power output and to efficiently provide refrigeration. Thus, the present method and system provide a gain in the efficiency in the refrigeration system operated by gas turbines.

One embodiment of the present method and system relates to LNG production and the refrigeration facility is a LNG liquefaction plant. In LNG methods and systems, natural gas is produced from a field or well. The produced supply of natural gas is collected. The LNG liquefaction plant is utilized to process substantially all of the natural gas stream. The inlet air to the gas turbines can be chilled with a portion of refrigerant from the refrigeration system. Optionally, the inlet air to the gas turbines can also be cooled with a portion of LNG, which is regasified.

In the present methods and systems, the effect of monthly temperature variation of the location on the capacity of the refrigeration facility is stabilized. The capacity of the refrigeration facility can be sensitive to environmental temperature variation. The capacity of the refrigeration facility is determined by the total output of the gas turbine machines in the refrigeration system and it is challenging to maintain the power output at a stable and maximum level.

According to the present methods and system, it has been surprisingly discovered that consuming a portion of the refrigerant from the refrigeration system and using the cooling effect to cool the inlet air for the gas turbines can maintain the power output of the facility at a stable and maximum level. By making inlet air to gas turbines stable and constant throughout the entire year, the plant (or capital) utilization efficiency is also greatly improved. The gain in energy efficiency by reducing the temperature of the inlet air entering the gas turbines can compensate for the consumption of refrigerant. The optimal degrees of chilling are machine-specific.

The refrigeration system comprises a refrigeration loop. The refrigeration system can comprise a single stage or multi stage refrigeration loop. For example, the multistage refrigeration loop can be a two stage, three stage or four stage loop. In one embodiment, the refrigeration system comprises a two or three stage refrigeration loop. When a multistage refrigeration loop is used, the consumed portion of refrigerant can come from the first stage of the refrigeration loop.

The refrigerant used in the refrigeration system can be any suitable refrigerant. Suitable refrigerants include methane, ethane, propane, ammonia, a hydrofluorocarbon, a chlorofluorocarbon, a hydrochlorofluorocarbon, a bromofluorocarbon, a bromochlorofluorcarbon, or any combination thereof.

The heat transfer can be indirect and involve the use of a heat transfer fluid. Any suitable heat transfer fluids can be used. Suitable heat transfer fluids include methanol, ethanol, a glycol and water mixture, or any combination thereof.

In one embodiment the refrigerant is propane and the heat transfer fluid is methanol.

The heat transfer can be either direct or indirect. The inlet air entering the gas turbine can be chilled by exchanging heat with a refrigerant in the refrigeration loop. The inlet air can be chilled by exchanging heat with a heat transfer fluid, which has been cooled by exchanging heat with a refrigerant in the refrigeration loop. The inlet air can also be chilled by both.

In one embodiment, the temperature of the inlet air entering the gas turbines can be reduced by 10 to 40° F. from the ambient temperature of the refrigeration system. In an embodiment, the temperature of the inlet air entering the gas turbines can be reduced by at least 20° F. from the ambient temperature. In another embodiment, the temperature of the inlet air entering the gas turbines can be reduced to a temperature in a range of from about 40 to 55° F. or 45 to 55° F. In an additional embodiment, the temperature of the inlet air entering the gas turbine can be reduced from an ambient temperature in a range of from about 60 to about 120° F. to a temperature in a range of from about 45 to about 55° F. In a further embodiment, the temperature of the inlet air entering the gas turbine can be reduced from an ambient temperature in a range of from about 80 to about 120° F. to a temperature in a range of from about 42 to about 60° F.

In one embodiment, the efficiency of the gas turbines is increased by at least 3%. The efficiency may be increased by at least 3% by reducing the temperature of the inlet air from an ambient temperature of 90° F. to a temperature of 50° F.

By maintaining the inlet air for the gas turbines at a constant low temperature, the amount of power generated by the turbine remains high regardless of the ambient air temperature. By carefully regulating the refrigerant to be consumed for cooling, it is possible to control the refrigeration supply and maintain the inlet air to a gas turbine at a cool and stable level. Thus, the gas turbine output and efficiency can be maximized in all seasons and in all climates.

For facilities in tropical regions that have high average temperatures, which relatively stable, the present system and methods can be utilized to lower the average values to maximize turbine output. In the Arctic with low temperatures and large seasonal variations, the present system and methods can be utilized to mitigate the seasonal variations. In the desert with high average temperatures and large seasonal variation, the present system and methods can be utilized to lower the average temperature and maintain the stability of the temperature. FIG. 2 is a graph showing the monthly temperature variations at three locations. The portion of the refrigerant to be consumed is utilized to control the inlet air temperature and maintain the power output at a steady, maximum level. Therefore, facilities for refrigeration, including facilities for LNG production, can be built at a variety of locations without concern that the ambient air temperatures will affect the efficiency. During cold seasons or climates, the air conditioning requirement provided by the consumed refrigerant is reduced.

The gain in gas turbine output and efficiency can compensate for cost for the additional refrigerant that is consumed. The gain may be measured over the seasonal variations for climates with cold seasons and the additional production during colder seasons can be used to compensate for the additional energy required for initial refrigeration during warmer seasons.

One embodiment of the method and system is illustrated in FIG. 1. A refrigeration system is provided for air-chilling. The refrigeration system comprises a two stage refrigeration loop. A gas turbine drives a compressor for the refrigeration system. In the system, a portion of refrigerant is consumed and used for cooling the inlet air entering the gas turbine of the refrigeration system. The refrigerant can cool the inlet air either directly or indirectly through the use of an intermediate heat transfer fluid.

In one embodiment a heat exchanger transfers heat from the portion of refrigerant to be consumed and cools an intermediate heat transfer fluid. A second heat transfer exchanger exchanges heat from the intermediate heat transfer fluid and reduces the temperature of inlet air entering the gas turbine. The second heat exchanger can comprise a cooling coil at an inlet of the gas turbine.

In one embodiment, the portion of refrigerant to be consumed is withdrawn from the first refrigeration loop. The portion of refrigerant to be consumed can be in a range of from 5 to 25% by weight of the total refrigerant. In one embodiment the portion of refrigerant to be consumed can be in a range of from about 10 to 25% by weight of the total refrigerant.

The refrigerant prior to reducing the temperature of the inlet air can be at a temperature of about −45 to about 45° F. In another embodiment, the refrigerant prior to reducing the temperature of the inlet air can be at a temperature of about −45 to about 30° F. When an intermediate heat transfer fluid is utilized for indirect heat transfer, the temperature of the heat transfer fluid prior to reducing the temperature of the inlet air can be at a temperature of about −45 to about 30° F. In another embodiment, the temperature of the heat transfer fluid prior to reducing the temperature of the inlet air can be at a temperature of about −45 to about 0° F. In a two stage refrigeration loop, the temperature of the refrigerant in the second loop can be in the range of about −100 to about 0° F.

After the cooling is complete, at least a portion of the consumed refrigerant can be recycled back to the refrigeration loop if desired.

The gas turbine of the refrigeration compressors condenses water vapor from the ambient air of the facility. The power generator for the facility may also condense water vapor from the ambient air. This condensed water is distilled quality water. Accordingly, the condensed water can be collected and used for other uses in the plant. For example, it can be used for wet compression, evaporative cooling, and/or fogging the inlet air to the gas turbines. The water can be used as plant process water such as hydrogen sulfide removal by passing natural gas through water or amine based solution. The water can be used for compressor circulation cooling and inlet humidity adjustment. Because it is distilled quality water, it can also be used for any use for which distilled water may be needed in the area of the plant. For example, it can be used as a source for drinking water or irrigation water as well. A source for drinking water or irrigation water may be particularly useful in desert locations.

The gas turbine according to the methods and systems described herein can be used to drive a compressor in the refrigeration system. The gas turbine can also be used to drive a steam generator or can be configured to generate electricity. Refrigeration systems driven by the one or more gas turbines can be utilized in LNG production, air separation, food storage, and ice-making.

In one embodiment, the presently claimed integrated refrigeration system and method can be used in a liquefied natural gas system. The liquefied natural gas system can have addition integration for chilling the inlet air of the gas turbines. Such an integrated LNG system and method are described in U.S. patent application entitled “Method to Maximize LNG Plant Capacity”, filed 30 Dec. 2010, Attorney Docket No. 70205.0221US01, the contents of which are herein incorporated by reference in their entirety. In this integrated liquefied natural gas system, natural gas is produced from a field or well and the produced supply of natural gas is collected as an inlet stream.

The inlet stream of natural gas is fed to a refrigeration system for reducing the temperature of the natural gas and condensing the natural gas to produce LNG (a liquefaction and refrigeration unit. The refrigeration system may be a single stage or multistage stage refrigeration loop. One or more gas turbines drive a compressor for the refrigeration system.

The liquefied product is then sent to a storage tank. From the storage tank, LNG can be collected to ship or transport to a remote market.

According to the integrated LNG system and method, a portion of the LNG is taken from the collection/storage tank for regasification. The portion of LNG is regasified in a regasification unit. The portion of the LNG to be regasified can be in the range of from 5% to 25% by weight of the total LNG produced. In another embodiment, the portion of the LNG to be regasified can be in the range of from 10% to 20% by weight of the total LNG produced. The regasification unit can be a vaporization heat exchanger for regasifying the portion of the LNG and cooling a heat transfer fluid. The heat transfer fluid can comprise methanol, ethanol, propane, an ethylene glycol and water mixture or any combination thereof. The heat transfer fluid can also take additional heat or refrigeration from auxiliary sources.

In the present methods and system, the heat transfer fluid takes additional refrigeration from the refrigeration loop comprising refrigerant. A second vaporization heat exchanger is present for consuming a portion of the refrigerant of the refrigeration loop and further cooling the heat transfer fluid.

A third heat exchanger is utilized for reducing the temperature of inlet air entering the gas turbine with the heat transfer fluid. This heat exchanger can comprise a cooling coil at an inlet of the gas turbine.

Thus, the portion of LNG to be regasified and the refrigerant to be consumed releases refrigeration and this is used to reduce the temperature of inlet air entering gas turbines of the refrigeration system in the LNG plant either directly or indirectly. As such, the temperature of inlet air is reduced by exchanging heat either directly or indirectly with the regasified portion of the LNG and the refrigerant. In one embodiment, the heat is exchanged indirectly through the use of an intermediate heat transfer fluid.

In this integrated LNG method and system, the regasified portion of LNG can be supplied to an outlet pipeline for supplying the regasified LNG to the domestic gas market.

The regasified LNG can be supplied to a natural gas pipeline for domestic or local natural gas production. By taking the inlet natural gas stream and creating LNG and then using the regasified LNG as the stream for the local natural gas market, the natural gas stream for the local market has any contaminants removed by the LNG process. Therefore, a separate facility is not required to remove contaminants, such as sulfur and carbon dioxide, from the natural gas before providing it to the domestic energy market.

If the regasified portion of the LNG is not needed for domestic natural gas production, or it is not all needed, the regasified LNG, or a portion of the regasified LNG, can be recycled to the refrigeration system to provide LNG.

The regasified LNG does not require an additional separate cleaning facility prior to use as domestic natural gas because it is cleaned sufficiently in the liquefaction process. Accordingly, the regasified portion of the LNG can be exported directly by pipeline for use in a local or domestic natural gas market. Because the regasified LNG has substantially all contaminants removed by the LNG process, the regasified LNG is cleaner than natural gas typically recovered for local or domestic market production. Natural gas recovered for local or domestic market production is processed to remove contaminants, such as sulfur and carbon dioxide, to meet pipeline specifications.

The regasified LNG can also be used to blend with natural gas directly collected for domestic production to meet pipeline specifications. When the regasified LNG is blended with natural gas, the natural gas can be processed less severely removing fewer contaminants so that the natural gas alone would not meet pipeline specifications. But the blend can meet pipeline specifications. The regasified LNG can be blended with natural gas, which has been not processed or has been processed less severely, and the blend meets pipeline specifications. For example, in cooler seasons it may be possible to blend high purity, regasified LNG with unprocessed or less processed natural gas and meet pipeline specifications for domestic gas production.

The gas turbine of the refrigeration compressors condenses water vapor from the ambient air of the facility. The power generator for the LNG plant may also condense water vapor from the ambient air. This condensed water is distilled quality water. Accordingly, the condensed water can be collected and used for other uses in the plant. For example, it can be used for wet compression, evaporative cooling, and/or fogging the inlet air to the gas turbines. The water can be used as plant process water such as hydrogen sulfide removal by passing natural gas through water or amine based solution. The water can be used for compressor circulation cooling and inlet humidity adjustment. Because it is distilled quality water, it can also be used for any use for which distilled water may be needed in the area of the plant. For example, it can be used as a source for drinking water or irrigation water as well. A source for drinking water or irrigation water may be particularly useful in desert locations.

Accordingly, with the present method and system, integration is utilized to increase the gas turbine power output in the LNG plant and to provide a natural gas stream suitable for the domestic or local natural gas market. The gain in energy efficiency by reducing the temperature of the inlet air entering the gas turbines can compensate for the amount of energy required to produce the portion of LNG, which is later regasified and can compensate for the refrigerant that is consumed.

In the integrated methods for operating a liquefied natural gas plant as disclosed herein, a single liquefied natural gas plant is utilized to create natural gas for a local gas market and liquefied natural gas for transport to a remote market. The process comprises cooling and condensing a natural gas stream in a LNG facility comprising a refrigeration system to produce LNG. One or more gas turbines are used to operate compressors for the refrigeration system of the LNG plant. A portion of the LNG is taken to be regasified. A portion of the refrigerant from the refrigeration is system is consumed. The temperature of inlet air entering the gas turbines of the refrigeration system is reduced by exchanging heat with the portion of the LNG to be regasified and with the refrigerant to be consumed, either directly or indirectly. In certain embodiments, an intermediate heat transfer fluid is used to take refrigeration from the portion of the LNG to be regasified and from the consumed refrigerant and the intermediate heat transfer fluid is used to cool the inlet air. The LNG produced from the facility is shipped to remote markets and at least a portion of the regasified LNG can be supplied to an outlet pipeline for local gas markets.

In the presently disclosed methods and system, the improvement comprises consuming a portion of the refrigerant to cool inlet air to the gas turbines. In the integrated LNG method and systems, the improvement further comprises converting substantially all of the produced natural gas stream from a well or field to LNG and then regasifying a portion. In regasifying a portion of the LNG, the regasification process is also used to chill inlet air to gas turbines used in the refrigeration system of the LNG plant. This approach enhances the GT power output and efficiency which, in turn, increases the LNG production of the plant. The gain in efficiency in LNG production can compensate for the additional cost in energy and consumption of the refrigerant.

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made without departing from the spirit and scope thereof. 

1. An integrated system for refrigeration comprising: (a) a refrigeration system comprising a refrigeration loop for air-chilling; (b) a gas turbine for driving a compressor for the refrigeration system; (c) a heat exchanger for consuming a portion of refrigerant from the refrigeration system and cooling a heat transfer fluid; and (d) a second heat exchanger for reducing the temperature of inlet air entering the gas turbine with the heat transfer fluid.
 2. The integrated system of claim 1, wherein the refrigeration is for LNG production, air separation, food storage, or ice-making.
 3. The integrated system of claim 1, wherein the refrigerant comprises methane, ethane, propane, ammonia, a hydrofluorocarbon, a chlorofluorocarbon, a hydrochlorofluorocarbon, a bromofluorocarbon, a bromochlorofluorocarbon, or any combination thereof.
 4. The integrated system of claim 1, wherein a gain in energy efficiency by reducing the temperature of the inlet air entering the gas turbine compensates for an amount of energy required for chilling and consuming the portion of refrigerant in step (c).
 5. The integrated system of claim 1, wherein the heat transfer fluid comprises methanol, ethanol, a glycol and water mixture, or any combination thereof.
 6. The integrated system of claim 1, comprising a single stage, two stage or three stage refrigeration loop.
 7. The integrated system of claim 1, wherein the portion of the refrigerant consumed is in a range from 5% to 25% by weight.
 8. The integrated system of claim 1, wherein the portion of the refrigerant consumed is in a range from 10% to 20% by weight.
 9. The integrated system of claim 1, wherein the second heat exchanger comprises a cooling coil at an inlet of the gas turbine.
 10. The integrated system of claim 1, wherein the temperature of the inlet air entering the gas turbine is reduced by 10 to 40° F. from ambient temperature.
 11. The integrated system of claim 1, wherein the temperature of the inlet air entering the gas turbine is reduced from an ambient temperature in a range from about 60 to about 120° F. to a temperature in a range from about 45 to about 55° F.
 12. The integrated system of claim 1, wherein the temperature of the inlet air entering the gas turbine is reduced to a temperature in a range from about 45 to about 55° F.
 13. The integrated system of claim 1, wherein an efficiency of the gas turbine is increased by at least 3% by reducing the temperature of the inlet air from 90 to 50° F.
 14. The integrated system of claim 1, wherein the refrigerant prior to reducing the temperature of the inlet air is at a temperature of from about −45 to about 45° F.
 15. The integrated system of claim 1, wherein the heat transfer fluid prior to reducing the temperature of the inlet air is at a temperature of from about −45 to about 30° F.
 16. The integrated system of claim 1, wherein the refrigerant comprises propane and the heat transfer fluid comprises methanol.
 17. An integrated method of maximizing gas turbine output for a refrigeration loop comprising: (a) operating a refrigeration loop for chilling processes; (b) operating a gas turbine to drive a compressor for a the refrigeration loop; (c) gasifying a portion of refrigerant from the refrigeration system; and (d) reducing the temperature of inlet air entering the gas turbines by exchanging heat with the gasified portion of refrigerant either directly or indirectly.
 18. The integrated method of claim 17, wherein the refrigeration is for LNG production, air separation, food storage, or ice-making.
 19. The integrated method of claim 17, comprising a single stage, two stage, or three stage refrigeration loop.
 20. The integrated method of claim 17, wherein the refrigerant comprises methane, ethane, propane, ammonia, a hydrofluorocarbon, a chlorofluorocarbon, a hydrochlorofluorocarbon, a bromofluorocarbon, a bromochlorofluorocarbon, or any combination thereof.
 21. The integrated method of claim 17, wherein a gain in energy efficiency by reducing the temperature of the inlet air entering the gas turbine compensates for an amount of energy required for chilling and consuming the portion of refrigerant in step (c).
 22. The integrated method of claim 17, wherein the temperature of inlet air is reduced by exchanging heat indirectly with the regasified portion of refrigerant using an intermediate heat transfer fluid.
 23. The integrated method of claim 22, wherein the heat transfer fluid comprises methanol, ethanol, a glycol and water mixture, or any combination thereof.
 24. The integrated method of claim 17, wherein the temperature of the inlet air entering the gas turbine is reduced by 10 to 40° F. from ambient temperature.
 25. The integrated method of claim 17, wherein the temperature of the inlet air entering the gas turbine is reduced from an ambient temperature in a range from about 60 to about 120° F. to a temperature in a range from about 45 to about 55° F.
 26. The integrated method of claim 17, wherein an efficiency of the gas turbine is increased by at least 3% by reducing the temperature of the inlet air from 90 to 50° F.
 27. The integrated method of claim 17, further comprising recycling at least a portion of the consumed refrigerant to the refrigeration loop.
 28. The method of claim 17, further comprising a step of collecting water condensed from reducing the temperature of the inlet air.
 29. An integrated method for operating a liquefied natural gas (LNG) plant, the method comprising: (i) cooling and condensing a natural gas stream in a refrigeration system to produce liquefied natural gas (LNG); (ii) operating a gas turbine to drive a compressor for the refrigeration system; (iii) regasifying a portion of the LNG; (iv) consuming a portion of the refrigerant from the refrigeration system; and (iv) reducing the temperature of inlet air entering the gas turbine by exchanging heat with the regasified portion of the LNG and with the consumed portion of the refrigerant directly or indirectly.
 30. The integrated method of claim 29 further comprising supplying at least a portion of the regasified portion of the LNG to an outlet pipeline. 